Evaluating Virtual Fence Technology for Grazing Dairy Cows

Abstract

Virtual fence technology has the potential to alleviate labour and cost associated with current physical fencing in pasture-based dairy systems. However, there is limited knowledge regarding the effects of management practices and associated cow motivators on cattle learning and response to VF stimuli. This thesis aimed to evaluate how dairy cattle learn and respond to a virtual fence at the individual and herd level using a pre-commercial VF prototype (eShepherd®, Agersens, Melbourne, VIC) and determine the effect of feed restrictions and social motivators on these responses. The first experiment revealed that dairy cows learn at different rates when exposed to VF stimuli for the first time in a group setting vs as individuals, which has implications for the training requirements. Individual variation in learning and response, and feed and social motivation were identified as factors requiring further research. The effect of a restricted diet and associated hunger levels on the response of trained dairy cows to a VF, when contained from additional feed, was evaluated in the second experiment. Cows fed restricted ration received more stimuli and performed more VF breakthroughs in the test paddock context. To understand how these findings would translate in a commercial pasture-based system, a third experiment evaluated feed restriction on pasture. Dairy cows were successfully contained by a VF across a 10-day strip grazing setting, even when restricted to the previous day’s residual for two 24 h periods. The focus of the final experiment was to evaluate the social motivation identified across the experimental chapters and identified a minimum distance between two VF to inform the future VF requirements of group management. This thesis builds upon the application of a VF technology in pasture-based dairy systems, through understanding the role feed and social motivation has on VF response and containment.